/*`
* mp1000-seprom.c
*
* This file contains the Serial EEPROM code for the MP1000 board
*
* Copyright (C) 2005 Comdial Corporation
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <asm/hardware.h>
#include <asm/hardware/clps7111.h>
#include <asm/arch/mp1000-seprom.h>
/* If SepromInit() can initialize and checksum the seprom successfully, */
/* then it will point seprom_data_ptr at the shadow copy. */
static eeprom_struct seprom_data; /* shadow copy of seprom content */
eeprom_struct *seprom_data_ptr = 0; /* 0 => not initialized */
/*
* Port D Bit 5 is Chip Select for EEPROM
* Port E Bit 0 is Input, Data out from EEPROM
* Port E Bit 1 is Output, Data in to EEPROM
* Port E Bit 2 is Output, CLK to EEPROM
*/
static char *port_d_ptr = (char *)(CLPS7111_VIRT_BASE + PDDR);
static char *port_e_ptr = (char *)(CLPS7111_VIRT_BASE + PEDR);
#define NO_OF_SHORTS 64 // Device is 64 x 16 bits
#define ENABLE_RW 0
#define DISABLE_RW 1
static inline void toggle_seprom_clock(void)
{
*port_e_ptr |= HwPortESepromCLK;
*port_e_ptr &= ~(HwPortESepromCLK);
}
static inline void select_eeprom(void)
{
*port_d_ptr |= HwPortDEECS;
*port_e_ptr &= ~(HwPortESepromCLK);
}
static inline void deselect_eeprom(void)
{
*port_d_ptr &= ~(HwPortDEECS);
*port_e_ptr &= ~(HwPortESepromDIn);
}
/*
* GetSepromDataPtr - returns pointer to shadow (RAM) copy of seprom
* and returns 0 if seprom is not initialized or
* has a checksum error.
*/
eeprom_struct* get_seprom_ptr(void)
{
return seprom_data_ptr;
}
unsigned char* get_eeprom_mac_address(void)
{
return seprom_data_ptr->variant.eprom_struct.mac_Address;
}
/*
* ReadSProm, Physically reads data from the Serial PROM
*/
static void read_sprom(short address, int length, eeprom_struct *buffer)
{
short data = COMMAND_READ | (address & 0x3F);
short bit;
int i;
select_eeprom();
// Clock in 9 bits of the command
for (i = 0, bit = 0x100; i < 9; i++, bit >>= 1) {
if (data & bit)
*port_e_ptr |= HwPortESepromDIn;
else
*port_e_ptr &= ~(HwPortESepromDIn);
toggle_seprom_clock();
}
//
// Now read one or more shorts of data from the Seprom
//
while (length-- > 0) {
data = 0;
// Read 16 bits at a time
for (i = 0; i < 16; i++) {
data <<= 1;
toggle_seprom_clock();
data |= *port_e_ptr & HwPortESepromDOut;
}
buffer->variant.eprom_short_data[address++] = data;
}
deselect_eeprom();
return;
}
/*
* ReadSerialPROM
*
* Input: Pointer to array of 64 x 16 Bits
*
* Output: if no problem reading data is filled in
*/
static void read_serial_prom(eeprom_struct *data)
{
read_sprom(0, 64, data);
}
//
// Compute Serial EEPROM checksum
//
// Input: Pointer to struct with Eprom data
//
// Output: The computed Eprom checksum
//
static short compute_seprom_checksum(eeprom_struct *data)
{
short checksum = 0;
int i;
for (i = 0; i < 126; i++) {
checksum += (short)data->variant.eprom_byte_data[i];
}
return((short)(0x5555 - (checksum & 0xFFFF)));
}
//
// Make sure the data port bits for the SEPROM are correctly initialised
//
void __init seprom_init(void)
{
short checksum;
// Init Port D
*(char *)(CLPS7111_VIRT_BASE + PDDDR) = 0x0;
*(char *)(CLPS7111_VIRT_BASE + PDDR) = 0x15;
// Init Port E
*(int *)(CLPS7111_VIRT_BASE + PEDDR) = 0x06;
*(int *)(CLPS7111_VIRT_BASE + PEDR) = 0x04;
//
// Make sure that EEPROM struct size never exceeds 128 bytes
//
if (sizeof(eeprom_struct) > 128) {
panic("Serial PROM struct size > 128, aborting read\n");
}
read_serial_prom(&seprom_data);
checksum = compute_seprom_checksum(&seprom_data);
if (checksum != seprom_data.variant.eprom_short_data[63]) {
panic("Serial EEPROM checksum failed\n");
}
seprom_data_ptr = &seprom_data;
}
